Development of a energy-producing, high-rate wastewater treatment system, it is decreasing of production of greenhouse effect gas and excess sludge

点击翻译按钮获取中文摘要

We have proposed sewage treatment system which consists of an UASB reactor as an anaerobic pre-treatment unit and an aerobic post-treatment unit. The aerobic unit is composed of a combination of a tricking filter reactor and a fluidized bed reactor in order to polish up the UASB effluent. The feasibility test feeding raw sewage for over 250 days was carried out with 7.18 m^3 pilot plant system at a municipal sewage treatment plant. Circulation of a part of the tricking filter effluent stream to the UASB as supplying a sulfate source improved the final effluent quality of the system. Influent unfiltered BOD of 303 mg/L decreased to 150 mg/L in UASB effluent and subsequently to 13 mg/L in the aerobic unit effluent for 12 hours in the HRT of whole system. Vial-activity batch tests suggested that the main electron flow for BOD oxidation in the UASB sludge shifted completely from methane production to sulfate reduction after 90 days operation.